The present invention relates to a portable hand-held apparatus for punching steel studs to form holes of sufficient size to allow wiring and piping to extend therethrough, and sufficiently lacking sharp tongues or flanges that would damage the wiring or piping, and to a control circuit for such an apparatus.
Steel frame homes and structures are becoming widespread. Steel frames have many advantages over traditional wooden frames. Steel frames are termite, rust, and rot proof. Further, steel frames are non-combustible, energy efficient, and resistant to poor weather and active seismic conditions.
Steel framing is made from light gauge galvanized steel cold formed into C-shaped cross-section components. Design changes are minimized by choosing components that match lumber dimensions, particularly when converting a wooden frame design to a steel frame design. Studs come in all sizes; however, most builders use 3 ⅝ inch and 5 xc2xd inch sizes that match wood frame dimensions.
When building steel frame homes and structures, it is necessary to have holes punched in the studs. These punched holes, sometimes called knock-outs, accommodate plumbing and electrical wiring by allowing pipes and/or wires to run through the holes. Steel studs may be purchased with preformed holes. Many times, the preformed holes are not in the desired locations, or there are no preformed holes. In these situations, the builder must form the holes in the steel stud wherever the holes are needed.
One way to form these holes is to use an acetylene torch to cut the holes. Using an acetylene torch to cut holes in steel studs is inconvenient for a builder. Another way to form holes in steel studs is with a large mechanical lever type piercer and die tool, such as that described in U.S. Pat. No. 5,287,716 issued to Szulc. Because a builder may not realize where it is desired to form holes in the steel studs until the frame is at least partially constructed, forming the holes is difficult. Many times, it is not possible to position the large lever type tool about the steel frame to form the holes because of the large size of the lever type tool, and because of the space constraints of the partially constructed frame. Further, sometimes it is difficult to align the holes on adjacent studs such that piping may be routed therethrough without additional difficulties. Still further, smaller lever type tools are generally only useful for forming small holes such as screw holes, and are not designed to form holes sized for wiring and/or piping.
It is therefore, an object of the present invention to provide a compact hand held apparatus for punching steel studs and a control circuit for such an apparatus.
In carrying out the above object, a portable hand-held apparatus for punching light gauge steel framing studs used in building construction to form holes of sufficient size to allow building wiring and piping to extend therethrough is provided. The apparatus comprises a frame, a punch and die assembly, a driving mechanism, an assertable limit switch, an assertable main switch, and a control circuit. The punch and die assembly is supported by the frame and includes a punch and a die mounted opposite each other for movement relative to each other. The die has a body defining a cavity for receiving the punch. A driving mechanism is mounted to the frame and selectively operable to drive the punch and die assembly over a working cycle including a deactuated position and an actuated position. In the deactuated position, the punch and the die are spaced apart with the stud position therebetween. In the actuated position, the punch extends into the die cavity by punching through the stud to form the punched hole. The limit switch is asserted when the punch and die assembly is in the deactuated position. The main switch is assertable by a user.
The control circuit is connected to the limit switch and the main switch, and has an output connected to the driving mechanism. The control circuit is configured to selectively operate the driving mechanism in response to assertion of the main switch by the user to drive the punch and die assembly from the deactuated position, over the working cycle, through the actuated position to form the punched hole, and continues to drive the punch and die assembly to the deactuated position to complete the cycle and assert the limit switch. The control circuit is configured to halt operation of the driving mechanism in response to assertion of the limit switch.
In a preferred embodiment, the control circuit further comprises a timer configured to halt operation of the driving mechanism after a predetermined time elapses from the assertion of the main switch without the punch and die assembly completing the cycle.
In some embodiments, the driving mechanism is battery powered. In some embodiments, the driving mechanism is an electric motor. The motor preferably has a predetermined threshold current, and the apparatus preferably further comprises a current sensor. The current sensor is connected to the motor for sensing a motor current. The sensor is configured to provide an overload signal to the control circuit in response to the motor current exceeding the threshold current. Preferably, the control circuit is configured to halt operation of the electric motor upon receiving the overload signal.
In an alternative embodiment, the motor is operable in a first direction and in a second direction, and the control circuit is configured to reverse the direction of the motor upon receiving the overload signal. Further, in a preferred embodiment, the apparatus further comprises an overload action selection switch having a first state and a second state. The control circuit is configured to halt operation of the motor upon receiving the overload signal when the selection switch is in the first state. The control circuit is configured to reverse the direction of the motor upon receiving the overload signal when the selection switch is in the second state.
Further, preferably, the apparatus further comprises an assertable reverse switch connected to the control circuit. The control circuit is configured to operate the motor in a first direction when the reverse switch is deasserted (and the main switch is asserted) and to operate the motor in the second direction when the reverse switch is asserted. In some embodiments, the control circuit operates the motor in a second direction upon the assertion of the reverse switch followed by the assertion of the main switch. In other embodiments, assertion of the reverse switch immediately causes the motor to move in the second direction.
In a preferred embodiment, the apparatus further comprises a current sensor connected to the motor. The sensor is configured to provide a punching signal in response to the motor current exceeding a punching threshold current indicating that the punch has formed a hole. A counter holds a value representing a number of punched holes made with the apparatus, and receives the punching signal. The counter is incremented upon receiving the punching signal. Preferably, a display displays the value in the counter to the user so that the user knows when the punch should be replaced, or possibly when the battery should be replaced.
It is appreciated that an electric motor is used in preferred embodiments of the present invention, however, a turbine driven by a fluid source may be used instead of the electric motor, with the control circuit controlling a valve that provides pressurized fluid to the turbine.
In some embodiments, the frame includes a generally C-shaped portion including first and second halves. Each half includes an end, and the ends are spaced apart for holding the punch and the die and for receiving the stud between the punch and the die. The apparatus in these embodiments further comprises a slide member and an assertable safety switch. The slide member connects the first and second halves of the C-shaped frame portion and allows sliding movement of the die toward and away from the punch by moving the slide member. The assertable safety switch is asserted when the first and second frame portion halves are positioned adjacent each other, and is deasserted when the first and second portion halves are positioned apart from each other to function as an interlock switch. The control circuit is configured to selectively operate the driving mechanism while the safety switch is asserted and to block all operation of the driving mechanism while the safety switch is deasserted.
Further, in carrying out the present invention, a portable hand-held apparatus for punching light gauge steel framing studs used in building construction to form holes of sufficient size to allow building wiring and piping to extend therethrough is provided. The apparatus comprises a frame, a punch and die assembly, an electric motor, a current sensor, a counter, and a display. The punch and die assembly is supported by the frame, and includes a punch and a die mounted opposite each other for movement relative to each other. The die has a body defining a cavity for receiving the punch. The electric motor is mounted to the frame and is selectively operable to drive the punch and die assembly over a working cycle, including a deactuated position and an actuated position. The motor has a predetermined punching threshold current.
The current sensor is connected to the motor. The sensor is configured to provide a punching signal in response to the motor current exceeding the punching current threshold indicating that the punched hole has been formed. The counter holds a value representing a number of punched holes made with the apparatus and receives the punching signal. The counter increments the counter value upon receiving the punching signal. The display displays the value in the counter to the user. The counter value may indicate to the user, for example, when the punch should be replaced or when the battery should be recharged.
Still further, in carrying out the present invention, a portable hand-held apparatus for punching knock-outs out of light gauge steel framing studs used in building construction to form holes of sufficient size to allow building wiring and piping to extend therethrough is provided. The apparatus comprises a compact hand-held frame having a generally C-shaped portion with spaced apart ends for receiving a stud therebetween. The frame includes a handle for gripping by a user. The apparatus further comprises a punch and die assembly, an actuatable driving mechanism, an assertable limit switch, an assertable main switch, and a control circuit. The punch and die assembly includes a punch and a die mounted opposite each other at the ends of the C-shaped frame portion. The punch and the die are mounted for movement relative to each other, and the die has a body defining a cavity. The punch is configured with respect to the cavity such that punching a hole produces a knock-out. The driving mechanism is mounted to the frame and operable to drive the punch and die assembly over a working cycle including a deactuated position and an actuated position. The limit switch is asserted when the punch and die assembly is in the deactuated position. The main switch is assertable by user.
The control circuit is connected to the limit switch and to the main switch, and has an output connected to the driving mechanism. The control circuit is configured to selectively operate the driving mechanism in response to assertion of the main switch by the user to drive the punch and die assembly from the deactuated position, over the working cycle, through the actuated position to form the punched hole and continues to drive the punch and die assembly to the deactuated position to complete the cycle and assert the limit switch. The control circuit is configured to halt operation of the driving mechanism in response to assertion of the limit switch.
Still further, in carrying out the present invention, a portable hand-held apparatus for punching knock outs out of light gauge steel framing studs used in building construction to form holes of sufficient size to allow building wiring and piping to extend therethrough is provided. The apparatus comprises a compact hand-held frame having a generally C-shaped portion with spaced apart ends for receiving a stud therebetween and a handle for gripping by a user. The apparatus further comprises a punch and die assembly, an electric motor, a current sensor, a counter, and a display. The motor has a predetermined punching threshold current and the current sensor is connected to the motor. The sensor is configured to provide a punching signal in response to the motor current exceeding the punching threshold current indicating that the punched hole has been formed. The counter holds a value representing the number of punched holes made with the apparatus, and receives the punching signal. The counter increments the value upon receiving the punching signal. The display displays the value in the counter to the user. The punch is configured with respect to a cavity defined by the die such that punching a hole produces a knock-out.
Even further, in carrying out the present invention, a portable hand-held apparatus for punching light gauge steel framing studs used in building construction to form holes of sufficient size to allow building wiring and piping to extend therethrough is provided. The apparatus comprises a frame, a punch and die assembly, and a driving mechanism. The apparatus further comprises an assertable first limit switch, an assertable main switch, and a control circuit. The first limit switch is asserted when the punch and die assembly is in the deactuated position. The main switch is assertable by a user. The control circuit is connected to the first limit switch and the main switch, and has an output connected to the driving mechanism. The control circuit is configured with an interlock circuit to allow selective operation of the driving mechanism in response to a momentary assertion of the main switch by the user to drive the punch and the die assembly. The punch and the die assembly is driven from the deactuated position, over the working cycle, through the actuated position, to form the punched hole. The control circuit is further configured to halt operation of the driving mechanism when the first limit switch is asserted after driving the punch and die assembly over the working cycle to the deactuated position.
In this embodiment of the present invention, preferably, the interlock circuit is configured to maintain a power connection to the control circuit after the control circuit halts the driving mechanism. Further, the control circuit preferably includes a timer. The timer may be utilized together with other aspects of the control circuit to provide enhanced control over the apparatus, as explained in the below description of preferred control circuit features.
Preferably, the control circuit is configured to reset the interlock circuit and disconnect the power connection to the control circuit when the timer exceeds a power down threshold. The timer is reset by the momentary assertion of the main switch. Preferably, the control circuit is configured to halt the driving mechanism when the timer exceeds an initial movement threshold before the first limit switch is deasserted. Further, preferably, the apparatus further comprises an assertable second limit switch that is asserted when the punch and die assembly has moved sufficiently from the deactuated position toward the actuated position such that the punched hole has been formed. The control circuit is configured to halt the driving mechanism when the timer exceeds a punch time out threshold before the second limit switch is asserted. Alternatively, the control circuit is configured to reverse the driving mechanism when the timer exceeds a punch time out threshold before the second limit switch is asserted. Further, the control circuit may halt the driving mechanism when the timer exceeds a reverse return time out threshold before the first limit switch is asserted after the reversing of the driving mechanism. And further, preferably, the control circuit is configured to halt the driving mechanism when the timer exceeds a forward return time out threshold before the first limit switch is asserted after the punch and die assembly begins the working cycle. In a preferred embodiment, the apparatus further comprises an assertable safety switch. The control circuit is configured to prevent operation of the driving mechanism while the safety switch is deasserted.
Preferred implementations utilize a compact hand-held frame having a generally C-shaped portion with spaced apart ends for receiving the stud therebetween. More preferably, the punch is configured with respect to the cavity such that punching a hole produces a knock-out.
The advantages accruing to the present invention are numerous. For example, the control circuit in some embodiments of the present invention allows a main switch to selectively operate the driving mechanism, while a limit switch detects when the punch is in the home or fully retracted position to stop the punch on the completion of the working cycle. Further, in some embodiments, a current sensor detects the current passing through an electric drive motor. The sensor is connected to a counter that counts holes formed. A display may indicate the value in the counter to a user to let the user know when the punch and/or die should be changed or when the battery should be recharged.
Further, embodiments of the present invention provide a compact hand-held tool for punching steel studs to form holes of sufficient size to allow wiring and piping to extend therethrough. In a preferred construction, a gross adjust mechanism and undercut jaws provide tool versatility, particularly for punching holes in steel studs which are already secured with a partially constructed frame. Preferably, the punch is configured with respect to the die cavity such that punching the hole produces a knock-out. Still further, it is preferred that an annular gap between the punch and the die cavity, when the punch is extended into the die cavity is sufficiently small such that the punched hole is substantially flangeless. That is, the hole sufficiently lacks sharp tongues or flanges that would damage the wiring or piping.
The above object and other objects, features, and advantages of the present invention are readily apparent from the following detailed description of the best mode for carrying out the invention when taken in connection with the accompanying drawings.